1. Field of the Invention
The present invention relates to an olefin polymerization reactor, a polyolefin production system, using a spouted-fluidized bed or spouted bed, and a process for producing polyolefins such as polyethylene and polypropylene by using such reactor and system.
2. Related Background Art
Olefin polymerization reactors which polymerize, within a vessel and in the presence of a catalyst, an olefin monomer fed in as a gas or liquid to form granular polyolefin particles are known to the art. Some of the reactors use an extremely simplified gas-phase polymerization process using a fluidized bed in which a step of dispersing, purifying, and recovering the solvent is omitted and granular polyolefin particles that do not require drying are obtained by polymerization.
Japanese Translation of PCT Application No. 2002-520426, European Patent Application No. 1484343, Japanese Translation of PCT Application Publication No. 2006-502263, Japanese Patent Application Laid-open No. S59-42039, Japanese Translation of PCT Application No. 2002-515516, Japanese Patent Application Laid-open No. S58-216735, WO 02/40547, and G Weickert, Chemie Ingenieur Technik 2005, 77, no. 8, p. 977 to p. 978 describe fluidized-bed apparatuses that include a variety of improvements. With the apparatuses described in Japanese Translation of PCT Application No. 2002-520426, European Patent Application Publication No. 1484343, Japanese Translation of PCT Application No. 2006-502263, and G Weickert, Chemie Ingenieur Technik 2005, 77, no. 8, p. 977 to p. 978, from among the aforementioned apparatuses, it is possible to produce polyolefins with a wide molecular weight distribution or polymer composition distribution by providing locally a zone in a region where polyolefin particle circulate, this zone being different in gas composition from other regions.
A technique, although not relating to the production of polyolefins, is also known by which solid particles are brought into contact with a fluid by using a flow called a spouted bed (see Akira Yokogawa, Funtai Kogaku Kaishi (Journal of the Society of Powder Technology, Japan), 1984, vol. 21, No. 11, p. 715 to p. 723). A technique is also known by which a draft tube is used as means for stabilizing a spouted bed (see Japanese Examined Patent Publication No. H6-76239, U.S. Pat. No. 4,373,272, Japanese Patent Publication No. 3352059; Yasuo Hatade et al. Funtai Kogaku Kaishi (Journal of the Society of Powder Technology, Japan), 1997, vol. 34, No. 5, p. 343 to p. 360; Sohei Takenaka et al. Kagaku Kogakukai, Dai 71 Kainen Kai Koen Yoshi (proceedings of the Society of Chemical Engineers, Japan, the 71st Meeting), J123, 2006; Toshifumi Ishikura, Kagaku Kogaku Rombunshu (collection of theses, the Chemical Engineers), 1996, VOL. 22, No. 3, p. 615 to p. 621). A technique is also known for using a draft tube in the production of polyolefins when a fluidized bed is used (see WO 02/40547).
From the standpoint of achieving high contact efficiency of particles and fluid, apparatuses using a flow called spouted-fluidized bed have been also studied (see Kishan B. Mathur et al. “SPOUTED BEDS”, ACADEMIC PRESS, INC. 1974, p. 263 to p. 264; Toshifumi Ishikura, Kagaku Kogaku Rombunshu (collection of theses, the Chemical Engineers) 1993, VOL. 19, No. 6, p. 1189 to p. 1192; Toshifumi Ishikura et al. Fukuoka Daigaku Kogaku Shuho (Collection of engineering theses, Fukuoka University, 1997, March, No. 58, p. 155 to p. 165). These apparatuses are provided with a gas introducing opening for forming a spouted bed and a dispersion plate for forming a fluidized bed. A technique of using a draft tube and a dispersion plate is described by Kishan B. Mathur et al. “SPOUTED BEDS”, ACADEMIC PRESS, INC. 1974, p. 263 to p. 264.